Non-carbonizing spark-plug.



N y,UNITED STATES PATENT OFFICE.

CHARLES KNOX HARDING, OF CHICAGO, ILLINOIS.

NoN-cAmsomzING SPARK-PLUG.

To all lwhom t may concern Be it known that I, CHARLES KNOX .HAR- D1NG,a citizen 0f the United States, residing y at Chicago, in the county of Cool; and State of Illinois, have invented a certaln new and to prevent the fouling of the parts with carbon. Viewed in its general aspects, my

invention consists in using a catalytic material to produce flamelesscatalytic combustion of part of the explosive vapor and keep the parts,-esp'ecially the insulator, free from deposits of carbon. It will be understood that in addition to the disadvantage arising when the sparking points of-a spark plug become coated with carbon, there is another serious cause of trouble in spark plugs, to-Wit: the deposition of carbon on.

the insulator, resulting in a short circuiting of the electrodes. The purpose of my invention is to prevent the deposition of solid carbon, especially on the insulator.

One form of' structure for carrying out thel inventionis illustrated in the accom panying drawings, in which:

Figure 1 is aview of the device chiefly in longitudinal section, and

Fig. 2 is a perspective of the catalytic cylinder which forms one of the elements of the device.

v Similar numerals the two views.

The shell or body 1 of the plug'is provided With external screw threads 2- near the bottom forlscrewing into the engine cylinder. This shell is madel of metal, usually iron or steel and, being screwed into the end of the cylinder, is thereby electri- 'cally grounded. The insulator 3 consists of porcelain or other suitable material ,and is held in place in the shell by a nut or bushing 4. As usual, the insulator is longitudinally apertured to receive the electrode rod 5. In the present instance the rod is externally threaded from top to bottom, and at the top is provided with a suitable nut 6 for binding the electric conductor (not shown) and holding it in electrical contact with the electrode rod. the lower end of the electrode rod is a sparking point 8 which coperates with a sparking point 9,

refer to similar partsin Specification of Letters Patent. I Patented Application led July 19',l 1916. Serial No. 110,02*?.

which is in electricall contact with the shell and is supported thereby. l

In so far as the parts have been thus far described, they may assume any standard or suitable form Without exceeding the scope of the invention. I will now describe the characteristics which are more intimately associated with the principle of the invention: Y

An'annular chamber 10 is lformed in the lower end of the insulator,vthe diameter of this chamber being ,considerably larger than the diameter of the electrode rod. Into this chamber I introduce la hollow cylinder 11 having catalytic properties. The Vinternal diameter of the cylinder is large enough'to accommodate the rod and the external diameter is small enough to leave a cylindrical space between it and the internal Wall of the insulator'. This cylinder is held in place by any suitable means, the present holding means comprising a nut 12 which screws on tothe rod and engages the upper end of the cylinder, and the nut 13 which screws on to the rod and engages the lower end of the cylinder. By preference, nut 13 has an external diameter smaller than the external diameter of the catalytic cylinder and -is partially .counter sunk into the end of th said L cylinder.

The catalytic body 11 may be composed of or treated with any suitable catalytic material which will produce llameless catalytic combustion, such, for example, as are described in my U. S. 'Patent No. 803,534, October 31, 1905, and No. 1,067,983, `July 22, 1913. .By preference, the catalytic structure is composed principally of the oxides of the radio active elements thorium and uranium as described in my later U. S. patent above mentioned. It will be understood that cataheated, the lower end'of the insulator 3- Will become heated, as will also the catalytic cylinder-11. i During the compression stroke which precedes' the explosion, and which precedes the jumping ofthe spark from one of the sparking points to the other, the explosive gaseous mixture will be forced up intothe chamber 10 surrounding the cylinder 11. As these parts are hot, albeit at a temperature considerably below the tempera-v bustible mixtures to be localized and not to propagate through the whole of the mixture. According to my present. understanding, the resulting benefit is at least two-fold. In the first place, as catalytic combustion is a true oxidizing action there will be less oxidizing remaining to be done to that simili portion of the explosive fuel-air mixture in the chamber 10 in contact with the insulator and catalytic body when the explosion occurs,

and hence, as a result of this pre-oxidizing,

the total period of oxidation will be mcreased with a consequent opportunity for the oxidation to be more complete by this double combustion produced by supplementing the ordinary combustion by preliminary flameless cata-lytic combustion and promot` ing complete and clean burning of that part of the charge which would tend otherwise to deposit carbon on the insulator. This is especially important where present day commercial gasolene is employed from which to obtain the explosive mixture. Such gasolene usually contains a certain 'percentage of oil having a relatively high boiling point, and in this the carbon aggregates occur in such form that the carbon cannot be completely oxidized in the short period of time afforded by the explosion or flaming combustion in the engine cylinder to entirely prevent the deposit of some small part of unburned carbon upon interior surfaces of the engine. In the second place, the parts of the insulator will be kept too hot for the deposition of carbon, or it' carbon would be deposited it will promptly be burned oil'. Thus in my device there will be prevented the deposition of carbon on the external surface of the lower end of the insulator where, if much carbon were deposited, there would be tendency for electric leakage across from the insulator to the adjacent part of the shell 2. As a result of my invention the parts will all be kept free fromcarbon, and

hence, will be kept in proper operating condition.

or structure may b'e employed that will produce sufficient heat during the time prior to the explosion of the mixture, and When the lexplosive mixture always contains sufficientL free and unburned oxygen to insure the burning off ofcarbon or carbon deposits from the hot insulator and which combustion does not iniiame the mixture or interfere with the regular electric ignition which explodes the entire mixture for the production of power.-

Having thus described my invention, wliatl claim as new and desire to secure by Letters Patent, is

1. A non carbonizing spark plug having electric sparking points, an insulator and catalytic means for producing ameless combustion of part of the explosive mixture in the vicinity of the insulator.

2. A non carbonizing spark Yplug having electric sparking points, an insulator means for electrically exploding the whole mixture, and catalytic means for producing lameless catalytic combustion of part of the mixture to heat the insulator.

istg

3. An electric non carbonizing spark plug having a shell, an insulator, means for electrically exploding the explosive mixturez and a catalytic body associated with said msulator for producing flameless catalytic com bustion of partof the mixture and thereby heating the insulator prior to the explo-l sion of the mixture when there is excess oxygen present to burn carbon ofi the insulator.

4. An electric non carbonizing spark plug for internal combustion engines, having a shell, sparking points, an insulator for insulating one of said points from the other, and a catalytic structure countersunk into and spaced apart from the internal wall of` said insulator that will produce heat by oxidizing a portion of the explosive mixture by contact combustion without inflaming the mixture and thereby maintain a high temperature of the insulator at a time when there is always an abunda-nce of free oxygen in the mixture to cause carbonto burn olf the hot insulator before the mixture is fouled by the explosion produced by the electric spark.

5. A non carbonizing spark plug for intive shell, an insulator mounted therein and spaced apart therefrom, electrodes for elec- I tricallyexplodingthe explosive mixture, a

catalytic body 1entering lnto a chamber in said'insulator and` means for passing some of the explosiye mixture into contact with said catalytic body to be oxidized with flamemlxture.4

p 6. An electric non-carbonizingy spark plug having means-for electrically exploding-the mixture, and a catalytic body for producing catalyticv lameless combustion of some of the explosive and thereby heating the insulatorand burning ofi" carbon mixture prior to the electric ignition thereof, said catalytic body containing thorium oxid and a radio actlve element associated therewith.

2ol combination'of 'a 'conductlve shell, an in sulator mountedtherem, sald insulator having 7. In a -non carbonizin'g'spark plug2 the a 'chamber in the bottomelectrodes, and a cylinder extending into said chamber and spaced apart therefrom said chamber com- Y municating with the inside of the engine cylinder and being thereby adapted to contact with a portion of part of the explosive mixture, said ,cylinder having radio active properties for producing iameless combustion 0f the explosive mixture thus heating the inao ,i

sulator and burning the carbon therefrom in the presence of oxygen ofthe unexploded `mixture before the electric ignition explodesA the whole charge for the productionv of power.

8. A spark plu comprising conducting electrodes, an insu ator therebetween'having interior surfaces forming part of a cham ber for the reception of a portion of the combustible mixture, and catalytlc means for roducing flameless combustlon of part of l t e mixture insaid chamber.

9. In a spark plug, an insulator and catalytic means for maintaining the insulator at the oxidizing temperature of carbon, the catalytic means operating over a period of timeappreciably longer than the period of t e inflammation of the combustible mixture.

In witness whereof, I have hereunto subscribedmy name. i

e CHARLES KNOX HARDING. 

